1. Field of the Invention
The present invention relates to a LED bulb and, more particularly, to a high illumination LED bulb with a full emission angle.
2. Description of the Related Art
As the green energy policy is highly promoted in international society, many advanced countries have thus set up the utilization deadline for tungsten bulbs. Light-emitting diode (LED) bulbs thus gradually enter the replacement market of tungsten bulbs.
Light emitting modules of conventional tungsten-filament bulbs radiate 360 degree projection light, while light bulbs 2, 3, and 4 (as shown in FIGS. 1, 2, and 3) using LED (SMD or chip) as light emitting modules can only radiate projection light with single direction. Thus, the designs of LED bulbs 2, 3, and 4 which project light in single direction can only be used for downlights projecting from ceiling to ground. If the LED bulbs 2, 3, 4 are to be used in a standing lamp 5 (see FIG. 19), a desk lamp 6 (FIG. 20), a wall lamp 7 (FIG. 21) or a bed lamp, the projection direction can only point to the ceiling (see D1 of FIG. 4). The projection light toward the floor can only rely on the reflected light shined on the slope of the lampshade of the standing lamp, desk lamp, wall lamp or bed lamp (see D2 of FIG. 4). It is obviously that the reflected light does not provide enough illumination intensity. Thus, after tungsten bulbs disappear in the market, such types of lamps will all be replaced by energy saving bulbs such as hot cathode fluorescent lamps (HCFL) or cold cathode fluorescent lamps (CCFL).
However, HCFL and CCFL type energy saving bulbs have ultraviolet light, electromagnetic wave, and radiation which are harmful to human body. Hence, if they are used close to human body, the injury will be larger. Furthermore, they contain composition such as Hg, Ar, and Ne, wherein Hg is harmful to human's brain, kidney and skin and is a contaminating material to the land too. Further, since the lamp bodies of HCFL and CCFL are usually of glass material, which are very fragile, when they are broken, Hg metal might get released, and once it is contacted by human bodies or is inhaled by human, it will cause brain and kidney disease. Moreover, it takes great cost to decompose the toxicity of the rejected product of HCFL, CCFL, and it does not meet the environmental requirement too. In addition, similar to fluorescent lamps, discharge of HCFL and CCFL type bulbs is a result of the impact of electrode with Hg gas. The generated light beam is of discontinuous light, which will cause vision fatigue of the eye and does not facilitate the reading.
Thus, how to design LED bulbs to match the utilization of lamps such as standing lamps, desk lamps, wall lamps or bed lamps and to increase the illumination scope of the projection light is really the top urgent matter of the LED industries; and it is an important way to promote the concept of environmental protection and energy saving.